Powder supply nozzle and overlaying method

Abstract

An object of the present invention is to provide a powder supply nozzle and an overlaying method which make it possible to restrain oxidation of a clad layer part and to produce a clad layer part with high quality. The invention provides a powder supply nozzle including: a laser emission part for irradiating a workpiece with a laser beam; and a powder supply part disposed in the periphery of the laser emission part and adapted to discharge a powder onto a laser-irradiated part, wherein a mechanism for guiding the air surrounding the laser-irradiated part to the exterior of the laser-irradiated part is provided in the periphery of the powder supply part.

1 . A powder supply nozzle comprising:
 a laser emission part which has a tubular innermost nozzle having a center axis coincident with a laser optic axis and connected to a laser beam condensing part and a gas supply source, the laser emission part radiating a laser beam while blowing off an inert gas, the radiating and blowing-off being performed from a tip of the innermost nozzle onto a workpiece; and   a powder supply part which has a tubular inner nozzle disposed in the periphery of the laser emission part and having a center axis coincident with the laser optic axis, the inner nozzle connected to a powder supply source, the space defined by the inner nozzle and the laser emission part being used as a powder passage, the powder supply part discharging a powder together with a carrier gas from the inner nozzle to a laser-irradiated part, wherein:   the powder supply nozzle includes a tubular outer nozzle disposed in the periphery of the powder supply part and having a center axis coincident with the laser optic axis;   the outer nozzle is connected to the gas supply source;   the space defined by the inner nozzle and the outer nozzle is used as a gas supply passage; and   a blow-off angle at a tip of the outer nozzle is within the range from 0°, exclusive, to 60°, inclusive, in a direction for spreading toward the outside of the nozzle relative to the laser optic axis.   
     
     
         2 . The powder supply nozzle according to  claim 1 , wherein:
 the outer nozzle is provided with a plurality of gas blow-off ports; and   a mechanism is provided for controlling the flow rate of a guide gas supplied through each of the gas blow-off ports by use of an external signal.   
     
     
         3 . The powder supply nozzle according to  claim 1 , wherein:
 the outer nozzle is connected to suction equipment;   the outer nozzle is provided with a plurality of suction ports; and   a mechanism is provided for controlling the flow rate of a gas sucked through each of the suction ports by use of an external signal.   
     
     
         4 . The powder supply nozzle according to  claim 1 , wherein:
 the powder supply nozzle is provided with a tubular outermost nozzle disposed in the periphery of the outer nozzle and connected to suction equipment; and   the space defined by the outer nozzle and the outermost nozzle is used as a suction passage.   
     
     
         5 . The powder supply nozzle according to  claim 1 , wherein:
 a tubular outermost nozzle is disposed in the periphery of the outer nozzle and connected to suction equipment;   the space defined by the outer nozzle and the outermost nozzle is used as a suction passage;   the outer nozzle and the outermost nozzle are provided with pluralities of gas blow-off ports and suction ports; and   a mechanism is provided for controlling the flow rate of a gas discharged or sucked through each of the blow-off ports and suction ports by use of an external signal.   
     
     
         6 . The powder supply nozzle according to  claim 1 , wherein:
 the powder supply nozzle is provided with the outer nozzle connected to suction equipment and with a tubular outermost nozzle disposed in the periphery of the outer nozzle and connected to the gas supply source;   a blow-off angle of the outermost nozzle is on the outer side relative to a blow-off angle of the outer nozzle; and   the space defined by the outer nozzle and the outermost nozzle is used as a gas supply passage.   
     
     
         7 . The powder supply nozzle according to  claim 1 , wherein:
 the powder supply nozzle is provided with the outer nozzle connected to suction equipment and with a tubular outermost nozzle disposed in the periphery of the outer nozzle and connected to the gas supply source;   a blow-off angle of the outermost nozzle is within the range from 0°, exclusive, to 60° inclusive, in a direction for spreading toward the outside of the nozzle relative to the laser optic axis;   the space defined by the outer nozzle and the outermost nozzle is used as a gas supply passage;   the outer nozzle and the outermost nozzle are provided with pluralities of gas blow-off ports and suction ports; and   a mechanism is provided for controlling the flow rate of a gas discharged or sucked through each of the blow-off ports and suction ports by use of an external signal.   
     
     
         8 . An overlaying method comprising:
 irradiating a workpiece with a laser beam while blowing an inert gas from a laser emission part onto the workpiece so as to supply a laser-irradiated part with a powder together with a carrier gas from a powder supply part comprised of the laser emission part and an inner nozzle provided in the periphery of the laser emission part and thereby to form a clad layer part, wherein:   a guide gas is blown off from an outer nozzle, which is disposed in the periphery of the powder supply part and connected to the gas supply source, at an angle within the range from 0°, exclusive, to 60°, inclusive, in a direction for spreading toward the outer side outside of the nozzle relative to a blow-off direction of the inert gas the laser optic axis.   
     
     
         9 . The overlaying method according to  claim 8 , wherein:
 the guide gas is blown off from the outer nozzle at flow velocity of the powder supplied from the powder supply part.   
     
     
         10 . The overlaying method according to  claim 8 , wherein:
 the guide gas is blown off from the outer nozzle at a flow velocity greater than the flow velocity of the powder supplied from the powder supply part;   the outer nozzle is provided with a plurality of blow-off ports and with a mechanism for controlling the flow rate of a gas supplied through each of the blow-off ports; and   the guide gas is blown off through each of the gas blow-off ports at an arbitrary flow rate.   
     
     
         11 . The overlaying method according to  claim 8 , wherein:
 an outermost nozzle connected to suction equipment is disposed in the periphery of the outer nozzle;   the guide gas is blown off from the outer nozzle at a flow velocity greater than the flow velocity of the powder supplied from the powder supply part; and   the air surrounding the inert gas is sucked through the outermost nozzle.   
     
     
         12 . The overlaying method according to  claim 8 , wherein:
 an outermost nozzle connected to suction equipment is disposed in the periphery of the outer nozzle;   the outer nozzle and the outermost nozzle are provided with pluralities of gas blow-off ports and suction ports;   a mechanism is provided for controlling the flow rate of   the guide gas supplied through each of the gas blow-off ports, and   a gas sucked through each of the suction ports; and   the air surrounding the inert gas is sucked through any one of the suction ports of the outer nozzle at any flow rates; and   the guide gas is blown off from any one of the blown-off ports of the outermost nozzle at any flow rates.   
     
     
         13 . An overlaying method comprising:
 irradiating a workpiece with a laser beam from a laser emission part while blowing an inert gas from a laser emission part onto the workpiece, so as to supply a laser-irradiated part with a powder together with a carrier gas from a powder supply part comprised of the laser emission part and an inner nozzle provided in the periphery of the laser emission part and thereby to form a clad layer part, wherein:   the air surrounding the inert gas is sucked through an outer nozzle disposed in the periphery of the powder supply part and connected to suction equipment;   an outermost nozzle connected to a gas supply source is disposed in the periphery of the outer nozzle; and   a guide gas is blown off from the outermost nozzle at an angle within the range from 0°, exclusive, to 60°, inclusive, in a direction for spreading toward the outside of the nozzle relative to the laser optic axis and at a flow velocity greater than the flow velocity of the powder supplied from the powder supply part.   
     
     
         14 . The overlaying method according to  claim 13 , wherein:
 the outer nozzle is provided with a plurality of suction ports;   a mechanism is provided by which to control the flow rate of a gas sucked through each of the suction ports; and   the air surrounding the inert gas is sucked through each of the suction ports at an arbitrary flow rate.   
     
     
         15 . The overlaying method according to  claim 13 , wherein:
 an outermost nozzle connected to a gas supply source is disposed in the periphery of the outer nozzle;   the outer nozzle and the outermost nozzle are provided with pluralities of gas blow-off ports and suction ports;   a mechanism is provided for controlling the flow rate of   the guide gas supplied through each of the gas blow-off ports and   the air sucked through each of the suction ports; and   the air surrounding the inert gas is sucked through any one of the suction ports of the outer nozzle at any flow rates; and   the guide gas is blown off from any one of the blown-off ports of the outermost nozzle at any flow rates.   
     
     
         16 - 21 . (canceled)